Artikel i vetenskaplig tidskrift, 2016

In this paper we present first results for prompt fission gamma-ray spectra (PFGS) characteristics from the spontaneous fission (sf) of Pu-240 and Pu-242. For Pu-242(sf) we obtained, after proper unfolding of the detector response, an average energy per photon (epsilon) over bar (gamma) = (0.843 +/- 0.012) MeV, an average multiplicity (M) over bar (gamma) = (6.72 +/- 0.07), and an average total gamma-ray energy release per fission (E) over bar (gamma,tot) = (5.66 +/- 0.06) MeV. The Pu-240(sf) emission spectrum was obtained by applying a so-called detector-response transformation function determined from the Pu-242 spectrum measured in exactly the same geometry. The results are an average energy per photon (epsilon) over bar = (0.80 +/- 0.07) MeV, the average multiplicity (M) over bar (gamma) = (8.2 +/- 0.4), and an average total gamma-ray energy release per fission (E) over bar (gamma,tot) = (6.6 +/- 0.5) MeV. The PFGS characteristics for Pu-242(sf) are in very good agreement with those from thermal-neutron-induced fission on Pu-241 and scales well with the corresponding prompt neutron multiplicity. Our results in the case of Pu-240(sf), although drawn from a limited number of events, show a significantly enhanced average multiplicity and average total energy, but may be understood from a different fragment yield distribution in Pu-240(sf) compared to that of Pu-242(sf).

Författare

S. Oberstedt

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

Andreas Oberstedt

Chalmers, Fysik

A. Gatera

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

A. Gook

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

F. J. Hambsch

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

A. Moens

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

G. Sibbens

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

D. Vanleeuw

European Commission Joint Research Centre, Institute for Reference Materials and Measurements

M. Vidali

European Commission Joint Research Centre, Institute for Reference Materials and Measurements